(1) Field of the Invention
This invention relates to a tape unit which has a head drum provided with a rotary magnetic head or heads, in which recording or reading of signals on a tape is carried out in the condition where a portion of the tape drawn out of a tape cassette mounted in a cassette mount section is wrapped around the head drum and in which the tape cassette is mounted into and removed from the cassette mount section through a cassette holder turnably supported on a chassis. More particularly, this invention relates to a tape unit of the above type which enables drive means, control means, various detection switches and the like for tape loading and tape unloading to be omitted, with the result of a marked reduction in cost and a more compact configuration, and which permits recording or reproduction (playback) to be started immediately after completion of an operation for closing an opening side of the cassette mount section.
(2) Description of the Prior Art
There have been known tape units in which a tape cassette is fitted into and removed from a cassette mount section through the function of a cassette holder, in the manner as follows. The cassette holder, in which the tape cassette is removably loaded, is coupled to a cover for closing and opening an opening side of the cassette mount section so that the cassette holder can be moved together with the cover. When the cover is moved to an open position for opening the opening side of the mount section, the cassette holder is moved to an ejection position, namely, a position for insertion and ejection of a tape cassette. When the cover is moved to a closed position for closing the opening side, on the other hand, the cassette holder is moved to a cassette mounting position, namely, a position for mounting the inserted tape cassette into the cassette mount section.
There have also been known rotary head type tape units, such as video tape recorders and rotary head digital audio taperecorders (R-DAT), in which recording or reading of signals on a tape is carried out by drawing out a predetermined length of tape from a tape cassette mounted in a cassette mount section, wrapping a portion of the drawn-out length of tape around an outer peripheral surface of a head drum comprising a rotary magnetic head or heads, and feeding the tape in the thus wrapped condition while rotating the magnetic head or heads.
During a tape loading operation for drawing out a predetermined length of tape from the tape cassette and during a tape unloading operation for taking up the drawn-out portion of tape onto one of the tape reels in the tape cassette, in use of the tape unit of the above type, rotation of the other tape reel is prevented by a lock means. In this condition, a reel base drive means for selective rotation in a tape takeup direction of two reel bases in engagement respectively with the two tape reels is located in a neutral position for non-linkage with any of the reel bases, and is prevented by a restricting means from moving in a direction for linkage. By these arrangements, the tape loading and unloading operations can be achieved smoothly, without slacking of the tape and without any excessive load on the reel bases. Further, the locking of the reel base and the position control over the reel base drive means are canceled substantially simultaneously with the completion of the tape loading so that no trouble occurs in tape feeding.
In the tape units of this type, the tape unloading operation is so scheduled that the movement of the cassette holder to the ejection position is enabled after the tape portion drawn out of the tape cassette is completely taken up onto one of the tape reels.
Therefore, the above type of tape unit requires a number of components, in addition to a mechanism for mounting and removing a tape cassette from the cassette mount section, a tape feeding means, a rotary head or heads for recording or playback, etc. One of the additionally required components is a tape loading mechanism which performs a tape loading operation, i.e. an operation of drawing out a portion of tape from a tape cassette, wrapping the tape portion around the head drum and passing the tape portion along a predetermined tape path, and a tape unloading operation. Another component needed is a drive means for moving a movable member of the tape loading mechanism which is moved between a position inside the tape cassette fitted in the cassette mount section and a position external to the tape cassette, to thereby serve for drawing out a portion of tape and for other functions. Besides, because a certain degree of strong force is necessary for tape loading, the drive means generally should be provided with a speed reduction mechanism composed of a gearing system, for obtaining an increased torque, in addition to a motor provided as a drive source. Furthermore, in order to prevent malfunction or to ensure automatic starting of a tape loading operation upon mounting of the tape cassette in position, the tape unit of this type needs a variety of sensors for detecting completion of the mounting of a tape cassette into the cassette mount section, completion of the tape loading, etc.
Moreover, due to the presence of the speed reduction mechanism provided for the drive means for the tape loading mechanism, as mentioned above, it requires some time to complete the tape loading or tape unloading operation. Accordingly, there must be a certain waiting time before recording or playback can be started after the movement of the cover to the closed position, or before the cover can be moved to the open position after recording or playback is finished.